This invention relates to a support tube for a felter element, and to a filter incorporating such a support tube.
Support tubes and filter elements of this kind are disclosed, for example, in German Offenlegungsschrift 37 23 807.
In such support tubes and filter elements it is a disadvantage that a plurality of different elements is necessary in order to make them, and consequently this calls for various tools and increases the cost of the finished product.
A one-piece support tube could be provided, which would require only one injection molding tool for its production. This, however, would lead to problems with regard to leakage.
It is therefore the object of the invention to provide a support tube and a filter element of the kind referred to above, which will eliminate the aforementioned disadvantages and produce a supporting tube and a filter element which will be easy to manufacture inexpensively and with good sealing qualities.
This object is achieved by the invention in that the supporting tube is composed especially of synthetic resin (plastic) and can be comprised of two substantially identical partial elements, each partial element having at least one inlet and outlet opening, as well as a radial and/or axial sealing area, and having at least one connecting area in communication with the other partial element. Providing sealing surfaces on the plastic partial elements and standardizing them reduces the number of elements needed, so that less costly products result.
An advantageous embodiment of the invention envisions constructing the radial sealing area substantially cylindrical. This cylindrical configuration provides the possibility of a uniform contact due to the consistent continuation of the supporting tube""s geometry, of the filter element on the supporting tube, for example.
Another advantageous embodiment of the invention envisions that the radial sealing area is conically configured. This has the advantage that, due to the conical configuration, when the supporting tube is assembled with, for example, the paper filter cartridge, a centering and positive contact in the sealing area will occur.
In another advantageous embodiment of the invention, it is envisioned that the connecting areas of the two partial elements are configured as a snap fastener. In this case it proves especially advantageous that no additional assembly work is needed to join these partial elements together.
Another advantageous refinement of the invention envisions that the connecting areas of the two partial elements are configured as a detent connection. In this case it is especially advantageous that a secure connection of both elements is produced, so that the stability of the entire element is assured.
An advantageous refinement of the invention envisions that the connecting areas of the two partial elements are configured as a bayonet lock. As in the case of the snap fastener, no additional assembly work is needed with this bayonet lock. The bayonet lock assures, in case of disassembly, a controlled opening of the entire joint between the two partial elements.
An additional advantageous refinement of the invention envisions that the two partial elements are identical, so that they can be manufactured in a single tool, which results in cost advantages.
Furthermore the object is also achieved by utilizing in a filter element a support tube as described above. Especially advantageous is the use of easily and inexpensively manufactured support tube elements which desirably originate from a single tool, and which furthermore, after installation the filter element, simultaneously perform a sealing function in the areas where it is needed.
An embodiment of the invention and its advantageous refinements are described in further detail hereinafter with reference to the accompanying drawings, wherein: